Recording capacity equivalent to an APS-H size? What does that mean in relation to it having a full-frame 35mm sensor?
Does it crop the sensor to get 4K video?
S35mm, the film format used in cinematography, is actually the size of APS-H. RED cameras have APS-H sensors, its the closest standard to the actual size of film.
"Full frame" 24x36mm is bigger than the full frame of cinema frames.
I would say it crops it, rather than resizing it. The idea of using APS-H size is having the correct angle of view for lenses.
Not quite. Super35 is 24.9mm wide.
The original Red has a 24.4mm wide chip, but it crops 16:9 video to 22.2mm wide.
Canon's version of APS-C is 22.3mm wide. So Red and the 7D have the same FoV for a given lens, and both can use cinema lenses and EF-S lenses.
The C300 gets it right with a 24.6mm sensor. The Alexa has a 23.8mm sensor. These cameras do it right.
The Red Epic and apparently this new dSLR have APS-H sensors for video, between 28mm and 30mm wide, the worst of both worlds--too wide for many cinema lenses (and, crucially important for Canon, too wide for APS-C lenses--the 17-55mm IS being nice for video) and too small to take advantage of big fast still primes. A bizarre no man's land. I get that this is just a modified 1dx, but that puts the price (likely) at half a c300. This is a very weird product. There are advantages to full frame video (the availability of lenses like the 24mm f1.4 for much less than cinema primes allowing you to go fast and wide) and advantages to APS-C (works with cinema lenses and EF-S, including the very nice 17-55mm IS) but this is an awkward sensor size. Not a deal breaker, but strange.